1. Field of the Present Disclosure
The present disclosure relates to an image processing apparatus.
2. Description of the Related Art
When scanning an image of a document that includes a crease, a crease part rises from its neighborhood and creates a shadow, and consequently in the scanned document image, the crease part appears as a linear image.
Therefore it is sometimes required to remove the image of the crease part distinguished from an object (i.e. a character, a figure, a photograph or the like) in the document.
An image processing apparatus (as a first image processing apparatus) identifies a spatial frequency distribution of the scanned document image, and determines a part having a low spatial frequency as a binding part.
Another image processing apparatus (as a second image processing apparatus) (a) scans a document image of a document without wrinkles and a document image of a document with wrinkles and detects wrinkles by comparing these document images or (b) scans a front surface image and a back surface image of a document with wrinkles and detects wrinkles by comparing these surface images.
However, a width of the crease is small and therefore the crease part has a high spatial frequency, and consequently in the aforementioned first image processing apparatus, it is difficult to distinguish the crease from an object in the document image.
Further, the aforementioned second image processing apparatus requires extra image scanning other than image scanning for a surface (i.e. single surface) that includes an object such as character, figure or photograph in the document.